Spintronics: It’s an emerging field in which the spin of electrons – rather than the charge – is used to process data. The challenge for integrating it into electronics is that the spin lasts only for a very short time. But researchers from the Netherlands' TU Delft have found a way to convert spin information into a predictable light signal at room temperature. The discovery could have applications in data centers, as an energy-efficient means of processing data.

The research, published in a recent edition of Science, revolved around two components: an extremely thin silver thread and a 2D material called tungsten disulfide. By attaching the silver thread to a four-atom-thick slice of tungsten disulfide, the researchers were able to create circularly-polarized light to create “excitons” – electrons that have bounced out of orbit – with a specific rotational direction.

As the excitons return to their original orbit, they emit an energy package in the form of light. The light contains the spin information, emitted in all directions. In order to put this information to use, the researchers returned to an earlier discovery about light moving along a nanowire: It is accompanied by a rotating electromagnetic field spinning clockwise on one side of the wire, and anti-clockwise on the other. The spin directions change when light moves in the opposite direction. This means that the electromagnetic field’s rotational direction is locked one-to-one with the direction traveled by light along the wire.

“We use this phenomenon as a type of lock combination,' explains Prof. Kobus Kuipers, of the university’s Kavli Institute of Nanoscience.

The spin information is launched in the right direction along the thread in 90 percent of cases – making it possible for fragile spin information to be converted into a light signal and transported over great distances. “You don't need a stream of electrons, and no heat is released,” adds Kuipers. “This makes it a very low-energy way of transferring information.”

As a combination of spintronics and nanophotonics, the research may result in what Kuipers refers to as “green” information processing strategies at the nanoscale.